The glass may be
broadly classified as:
1. Soda-lime glass
2. Potash lime
glass
3. Potash lead glass
4. Common glass and
5. Special glasses.
1. Soda Lime Glass:
It is mainly a mixture of sodium silicate and calcium silicate. It is fusible
at low temperature. In the fusion condition it can be blown or welded easily.
It is colourless. It is used as window panes and for the laboratory tubes and
apparatus.
2. Potash Lime Glass:
It is mainly a mixture of potassium silicate and calcium silicate. It is also
known as hard glass. It fuses at high temperature. It is used in the manufacture
of glass articles which have to withstand high temperatures.
3. Potash Lead Glass:
It is mainly a mixture of potassium silicate and lead silicate. It possesses
bright lustre and great refractive power. It is used in the manufacture of
artificial gems, electric bulbs, lenses, prisms etc.
4. Common Glass: It
is mainly a mixture of sodium silicate, calcium silicate and iron silicate. It
is brown, green or yellow in colour. It is mainly used in the manufacture of
medicine bottles.
5. Special Glasses:
Properties of glasses can be suitably altered by changing basic ingredients and
adding few more ingredients. It has now emerged as versatile material to meet
many special requirement in engineering. The following is the list of some of the special glasses:
(a) Fibre glass
(b) Foam glass
(c) Bullet proof
glass
(d) Structural glass
(e) Glass black
(f) Wired glass
(g) Ultraviolet ray
glass
(h) Perforated glass.